Monday, September 26, 2011

There, I fixed It! Part 2

Yoni's post is not ready yet, so I am stepping in a day early to make sure you get your fix.

The antenna on my car is supposed to retract into the back of my car when the radio is not on, but it doesn't.  As a result the antenna got a little bent, it was not a big deal.  However, one day while parking near a friends house I drove under a low hanging tree and really bent the antenna.  I knew that I had to act fast or loose the antenna entirely. 

Duct tape to the rescue!!!
Duct tape and wooden shish kebob skewers.
There, I fixed it.  Now the antenna is strong straight and I get better radio reception than I used to.

Thursday, September 22, 2011

There, I fixed it!

It's time for another theme week! (Most weeks start on Thursdays, right?) This time, it's "There, I fixed it."

We have a second-hand air conditioner in our guest bedroom. Unfortunately, this summer the "Master Control" knob broke:

The thermostat knob still works, and you can use a needle-nosed pliers to turn the "Master Control" peg which lies under the plastic panel, but it's annoying (and will probably eventually break the peg). So, I set the AC "Master Control" (which sounds like a term over-used in bad sci-fi movies) to medium cool (it's a small room) and devised a new on/off switch:
The extension cord runs from the hard-to-reach outlet behind the dresser. To turn the AC on, you simply plug it into the extension cord; to turn it off, just unplug!

There, I fixed it!

Saturday, September 17, 2011

specializing in all hair styles, lesson on signage

Specializing means to Confine oneself to providing one particular product or service

The sign says
"Tony's BARBER SALON specializing in all hair styles"
Maybe Tony is an immigrant and he thinks that specializing just means we can do.

Thursday, September 15, 2011

Not quite 22 megawatts

Jonathan/Yoni's insightful post on Sunday highlighted a limitation of electric cars. He calculated that a gasoline pump transfers energy to your car at a rate of around 22 megawatts. According to Wolfram|Alpha, this is around 3667-7333 average households' power consumption, or just over half the total power output of the largest US photovoltaic power plant.

This would be amazing if cars utilized 100% of the thermal energy output of gasoline combustion. But, automobile engines (like all heat engines) can not operate at 100% efficiency. According to Wikipedia, car engines operate at 15-20% efficiency.[wiki quoted source] This means that before anything else is taken into consideration, it's an order of magnitude less useful energy transferred. Electric motors, on the other hand, have efficiencies which approach 100%![source] So, even if the rate of energy transfer to the car is slow, the real question is what is the effective (useful) power.

So, I've come up with what I think is a good measure for this, which incorporates all the losses of energy inherent in the system: How long does it take to load the energy into the car required to travel a particular distance. Or, what is the (miles per energy)*(energy transfer rate), alternatively [and equivalently] (miles traveled)/(car energy transfer time). This value has units of [distance]/[time] and can be expressed in miles/min or miles/hr (or kph, for our metric friends). This is a great way to compare all cars in terms of usefullness and efficiency using a familiar unit.

For example, our Ford Focus gets 40mpg on the highway.[source] So, it's "usefulness speed" is: (40 miles/gallon)*(10 gallons/min) = 400 miles/minute, which works out to 24,000mph! A Ferrari 599 GTB Fiorano "usefulness speed" is (15 mpg)*(10 gpm) = 150 miles/minute, or 9,000 mph [source]  The Prius, at 48mpg is 480 miles/minute, or 28,800 mph. [source]

The Nissan Leaf, with a range of 100 miles/charge and a greater than seven hour home charge time (under ideal circumstances), has a useful speed of 0.23 miles/minutes, which is only 14 miles/hour. That makes it 0.05% as useful as my car, and 0.16% as useful as a Ferarri!

So, instead of focusing on top speed when buying a car, you can focus on top usefullness speed! You can even go one step further and look at top usefullness speed/cost. And, I agree with Jonathan/Yoni's conclusions: Until batteries and their charging methods improve drastically, gasoline wins by a landslide.

Note: I was trying to do these calculations with the Chevy Volt, but it requires a few too many assumptions.
Also Note: If anyone wants to estimate what a bicycle's useful speed is, the comments are open!

Wednesday, September 14, 2011

Truck 1, Wall 0

The Rutgers engineering buildings loading dock is located in the mechanical engineering wing.  Because it is a nasty 1960's type possibly sound barrier wall.  Well on Friday a truck hit the wall.

The truck didn't even get scratched.

Sunday, September 11, 2011

The gas station pumps energy at ~22 Megawatts

Gasoline pumps in america pump no faster than 10 gallons per minute [source].
Gasoline has an energy density of ~35 megajoules per liter.
[wiki quoted source (I have not double checked it)].
Therefore the power with which the gasoline pump transfers potential energy into your tank is:
(34.8 (megajoules / liter)) * ((10 US gallons) / (1 minute)) = 21.96 megawatts
For comparison, a typical circuit in your house can output a maximum of about 2,400 watts, or 0.0024 megawatts ... you would need almost 10 thousand household circuits to get the potential energy flowing into your electric car at the same rate. Of course no battery yet exist that can swallow up that energy so fast --- and you certainly couldn't store it for a week and then take it with you 100 miles down the road.

Thursday, September 08, 2011

Polishing silver with chemistry

I am not a chemist, not by a long shot. But I am lazy, and Stacy found a method online for polishing silver which required very little manual effort. See here. Basically, you put the silver in contact with some aluminum foil, pour on boiling water with lots of baking soda dissolved, and wait. According to that site, "In the reaction, sulfur atoms are transferred from silver to aluminum, freeing the silver metal and forming aluminum sulfide." Sounds like chemistry to me, but could be technobabble for all I know. So, being somewhat skeptical of many save-effort suggestions online, I checked with a chemist (thanks, notElon!) who said it should work, but suggested scuffing up the aluminum to help strip off the oxide coating.

With his endorsement, I set out to polish an heirloom pie server thing. Here it is in a pot lined with aluminum foil:

I boiled water, mixed in the baking soda, poured it on, and behold! A reaction!

Unsuprisingly, it smelled like sulfur (I assume that's the aluminum sulfide). Here's a video where you can see the bubbling and hear me commenting on the smell (in case you don't trust written-word Eli), and feel free to click-through to full-size:

In any case, it did a pretty good job and I'd do it again next time. Hooray for chemistry!

Thursday, September 01, 2011

I “LOVE” my Frances Stewart Baby Nurse

I want you to notice that this blog post is not written by Eli, something so hysterically funny happened that I had to come out of blogger retirement for this one.

Bless my mom, who wanted to make my life easier.  She hired a baby nurse for us to sit up with our newborn all night so we could get some rest.  She did that with our first son also and it was an enormous help.

The agency called as we were about to leave the hospital and said something about her being vegan and bringing her own food.  Whatever, we have our own dietary restrictions so we were totally cool with that, and vegan meant that she would be way less likely to treif up our kitchen.

Eli picked her up and she did have a bag of produce in tow.  However it quickly became apparent that this lady ate a LOT of veg.  And soon informed us that she would need to make regular trips to Whole Foods for us to purchase fresh organic produce for her just about every other day.

Later the same day she speculated aloud “Oh maybe I should close the door to the bathroom when I use it” aloud, after I walked by.

For two days we indulged Marlene’s organic produce habit, while she learned to close the door to the bathroom and spent hours and hours chopping her organic produce while our baby slept. 

Then came day three, she informed us it was time for her walk with the baby.  We asked her to delay until Eli and I could regroup, feeding the kid and catering for a crowd on Shabbos.  And I started to think, maybe this woman, who was sitting up with our child was more work than the child itself.

Finally, she asked me where I keep the bottled water in our house. We don’t have bottled water in our house, I don’t drink bottled water, my husband doesn’t drink bottled water and neither of my children drink bottled water.  It was at this point that I realized that the newborn was nowhere near as much of a pain as Marlene was, and we asked her to leave.  (Or rather in a particularly hormonal postpartum moment I sobbed “ELI MAKE HER GO AWAY NOW”)

After she left we realized she did accomplish Mom’s goal, she had given us the confidence in our parenting to parent independently, to relax around our kids and really enjoy them, just possibly not the way the Marlene or the Francis Stewart Agency would have intended.

I thought that was where the humorous interlude ended.  However, Monday, after our son’s bris, we got this in the mail.  And thus the humorous interlude is truly complete.